A full-diameter liquid-free device for oil and gas wells and oil and gas pipe

Abstract

The present invention relates to a full-diameter liquid-free device for oil and gas wells and an oil and gas pipe. The oil and gas well liquid-free oil and gas pipe comprises an oil and gas pipe and a full-diameter liquid-free device arranged at the top or bottom of the oil and gas pipe, wherein the oil and gas pipe is integrally connected, welded or threadedly connected to the full-diameter liquid-free device; the full-diameter liquid-free device comprises a pipe body, a main gas channel arranged at the center of the pipe body, an annular groove arranged on the inner wall of the pipe body and connected to the main gas channel, a gas branch channel arranged in the annular groove and an annular liquid receiving groove with an upward opening, wherein the gas branch channel passes through the annular liquid receiving groove. The present invention can make full use of the production layer pressure without occupying the central channel of the oil and gas pipe, thereby improving the gas liquid carrying capacity of the oil and gas well and the oil and gas recovery rate.

Description

Technical Field

[0001] The invention belongs to the field of oil and natural gas extraction equipment, and in particular relates to a full-diameter liquid accumulation-free device for oil and gas wells and an oil and gas pipe. Background Art

[0002] Oil and gas self-flowing wells usually have casing installed in the well, and a production string composed of several oil and gas pipes (also called oil pipes in this industry) connected end to end is installed in the casing. When in use, the gas-liquid mixture at the bottom of the oil and gas well is usually sprayed upward to the ground along the production string under the action of pressure difference, thereby realizing oil and gas extraction.

[0003] However, during the production process of natural gas wells, water is often produced in the gas wells along with the natural gas. In the early stage of exploitation, the energy of the production layer is sufficient, the natural gas flows fast, and the high-speed flowing gas can drive the liquid to discharge the water from the bottom of the well to the ground. However, as the energy of the production layer decreases, the natural gas production decreases, the flow rate decreases, and the gas's liquid-carrying capacity decreases. The water produced by the formation cannot be discharged and accumulates in the well. As more and more water accumulates, the height h of the water column in the well becomes higher and higher, and the liquid column pressure becomes greater and greater. The liquid column pressure directly acts on the production layer. When the liquid column pressure forms a balance with the pressure of the production layer itself, it will cause the gas well to be flooded, thereby affecting the exploitation of natural gas.

[0004] Similarly, in oil wells with gas and liquid coexisting, as the energy of the production layer decreases, the water content of the crude oil increases, the gas-liquid carrying capacity decreases, the slippage of the liquid column will become more and more serious, and eventually the oil well will stop flowing.

[0005] Therefore, it is crucial to fully utilize the production layer pressure in oil and gas wells where gas and liquid coexist, improve the gas's liquid-carrying capacity, and increase the oil and gas recovery rate.

[0006] In order to solve the above problems, several gas lift valves with different switch pressures are usually installed on the pipe column. When in use, high-pressure gas is injected into the casing through the booster box. The gas lift valve is opened step by step from high to low by using the difference between the casing annular pressure and the liquid column height. The gas in the casing enters the oil and gas pipe through the gas lift valve and mixes with the gas-liquid mixture in the pipe column, reducing the pressure of the liquid column in the pipe column on the bottom of the well and promoting the production of oil and gas. Since the gas content in the oil well is low and the crude oil content is high, the pressure of the liquid and the pressure of the gas in the casing are relatively different, which can ensure that the gas lift valve is opened as required. However, in the gas well, the natural gas content in the oil and gas pipe is high and the crude oil content is low, which leads to a smaller difference between the annular pressure of the casing and the pressure of the gas-liquid mixture in the oil and gas pipe, especially in the upper part of the oil and gas pipe (the higher the position of the gas-liquid mixture in the oil and gas pipe, the smaller the difference), and the pressure difference is often not enough to support the smooth opening of the gas lift valve, which makes it difficult to use this method normally in the gas well and difficult to achieve its desired effect.

[0007] To solve this problem, our R&D personnel had envisioned installing a one-way valve at the bottom of the pipe string to block the downward movement of the liquid. However, this measure has the following problems: During oil and gas production, in order to understand the reduction of oil and gas, it is often necessary to regularly lower measuring equipment from the oil and gas pipe to measure the pressure and temperature of the bottom hole liquid surface; in addition, after the oil and gas pipe is installed, some oil and gas wells also need to install throttles at the bottom of the well to control the production rate of oil and gas. After the above-mentioned liquid receiving device or one-way valve is installed in the central channel, the above-mentioned operation will undoubtedly be impossible to carry out, resulting in a series of problems due to the inability to measure the liquid level parameters and install the throttle in time.

[0008] Therefore, it is crucial to make full use of the production layer pressure, improve the gas-liquid carrying capacity of oil and gas wells, and increase the recovery rate of oil and gas, especially the recovery rate of natural gas in gas wells, without occupying the central channel of the oil and gas pipeline. Summary of the invention

[0009] The purpose of the present invention is to overcome the defects in the prior art and provide a full-diameter liquid-free device for oil and gas wells and an oil and gas pipe, which can be used not only in oil wells with associated oil and gas, but also in gas wells with associated oil and gas. It can make full use of the production layer pressure without occupying the central channel of the oil and gas pipe, thereby improving the gas-liquid carrying capacity of the oil and gas wells and the oil and gas recovery rate, especially the problem of low recovery rate of natural gas that cannot be solved by the prior art.

[0010] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0011] A full-bore liquid-free device comprises a tube body, a main gas channel arranged at the center of the tube body, an annular groove arranged on the inner wall of the tube body and connected to the main gas channel, a gas branch channel arranged in the annular groove and an annular liquid receiving groove with an upward opening, wherein the gas branch channel passes through the liquid receiving groove.

[0012] As a further technical solution, an annular guide plate is also arranged on the top wall of the annular groove, the inner wall of the annular guide plate is smoothly connected to the inner wall of the upper part of the tube body, and the lower part of the annular guide plate is inserted into the annular liquid receiving groove, thereby forming a bending passage in the annular liquid receiving groove.

[0013] As a further technical solution, an annular cylinder is provided on the inner wall of the tube body, and the annular cylinder and the inner wall of the tube body enclose an annular cavity. The main gas channel is provided at the center of the annular cylinder, and the annular liquid receiving groove is provided on the annular cylinder. The annular cylinder is also provided with a plurality of air inlets connecting the main gas channel and the annular cavity.

[0014] As a further technical solution, the annular cylinder is connected to the top wall gap of the annular groove, thereby forming a first channel connecting the annular cavity and the bending channel and an annular gas outlet connecting the bending channel and the main gas channel;

[0015] As a further technical solution, the air inlet, the annular cavity, the first channel, the bent passage, and the annular air outlet are connected in sequence to form the gas branch channel.

[0016] As a further technical solution, the annular tube includes an annular connecting plate arranged on the inner wall of the tube body, and an annular liquid receiving groove arranged on the annular connecting plate.

[0017] As a further technical solution, the air inlet is arranged on the annular connecting plate, and the position of the air inlet is higher than the lowest point of the annular cavity.

[0018] As a further technical solution, the annular liquid receiving groove is surrounded by an inner ring plate and an outer ring plate, and the upper surface of the inner ring plate is lower than the upper surface of the outer ring plate.

[0019] As a further technical solution, the tube body includes an upper tube body and a lower tube body, the outer wall of the upper tube body is provided with an annular groove, and the bottom of the lower tube body is provided with an annular tube adapted to the annular groove, the annular tube is arranged in the annular groove and is bonded, welded or detachably connected to the annular groove.

[0020] As a further technical solution, the detachable connection adopts a threaded connection.

[0021] As a further technical solution, the tube body is further provided with an inclined gas supply channel which is connected to the outside of the tube body and the main gas channel and / or the branch gas channel, and the gas supply channel is provided with a jet hole swirl block, and the jet hole swirl block is provided with a jet hole;

[0022] As a further technical solution, the distance from the top end of the air supply channel to the central axis of the tube body is smaller than the distance from the bottom end to the central axis of the tube body.

[0023] As a further technical solution, the jet hole includes a short tapered hole, a fine hole and a long tapered hole which are sequentially arranged and connected according to the gas flow direction, and the taper of the short tapered hole is greater than the taper of the long tapered hole.

[0024] As a further technical solution, a limiting boss is provided in the air supply channel, and a steel gasket (a gasket made of steel material) and an annular sealing gasket are provided between the limiting boss and the jet hole rotating block.

[0025] As a further technical solution, in the horizontal direction, the air supply channel is eccentrically arranged with the central axis of the tube body as the center.

[0026] A liquid-free oil and gas pipe for oil and gas wells, characterized in that it comprises an oil and gas pipe and a full-bore liquid-free device arranged at the top or bottom end of the oil and gas pipe, and the oil and gas pipe is integrally connected, welded or threadedly connected to the full-bore liquid-free device.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. When natural gas rises in the production string, the gas-liquid mixture is rubbed by the inner wall of the production string, and the speed will gradually decrease. The friction resistance of the production string is transmitted from the periphery of the pipe to the center of the pipe by the viscosity of the gas-liquid mixture. Therefore, the flow rate of the gas-liquid mixture decreases quickly near the inner wall of the production string, while the flow rate of the gas-liquid mixture in the center of the production string decreases slowly. This causes liquid to fall along the inner wall of the pipe body, thereby causing gas well flooding. In order to solve this problem, the present invention adds a full-diameter at each certain distance. The liquid accumulation-free device is provided with a liquid receiving groove and a guide plate on the inner wall of the pipe body, and a gas branch channel passing through the liquid receiving groove is provided on the inner wall of the pipe body. The liquid falling along the pipe wall is guided into the liquid receiving groove by the guide plate to prevent it from sliding to the bottom of the well. In the process of oil and gas rising along the central gas channel, part of the gas is diverted by the gas branch channel so that the liquid in the liquid receiving groove is taken out in the process of passing through the liquid receiving groove and continues to rise along the production pipe string, thereby avoiding the problem of overflow of the accumulated liquid caused by increasing liquid accumulation in the liquid receiving groove and continued sliding after the overflow. In addition, when natural gas is ejected from the gas branch pipeline, the upward airflow can be used to form an upward support force on the liquid on the pipe wall, which can further block the downward movement of the liquid on the pipe wall. In summary, the present invention greatly improves the liquid carrying capacity of natural gas by using the annular liquid receiving groove, the guide plate and the branch gas channel in combination, and avoids the problem of gas well flooding caused by the downward movement of liquid. Compared with the gas lift technology of oil and gas wells, it can be applied not only to oil wells, but also to gas wells, and does not require additional energy. The liquid carrying capacity of natural gas can be improved by using the energy of the production layer itself. It has wider applicability and lower cost.

[0029] 2. The present invention sets a bending channel in the liquid receiving tank, and the branch gas enters from one end of the bending channel and flows out from the other end, which maximizes the contact time between the gas and the liquid in the liquid receiving tank and increases the liquid carrying capacity of the gas.

[0030] 3. On the one hand, the present invention sets the upper surface of the inner ring plate of the annular liquid receiving groove lower than the outer ring plate, and on the other hand, sets the air inlet connecting the main gas channel and the annular cavity higher than the bottom wall of the annular cavity, thereby preventing the liquid in the annular liquid receiving groove from overflowing over the outer ring plate into the annular cavity, reducing the accumulation of liquid in the annular cavity, and preventing the gas branch channel from being blocked by a small amount of liquid accumulated at the bottom of the annular cavity, thereby affecting the air intake of the gas branch channel.

[0031] 4. The full-diameter liquid-free device of the present invention is assembled from an upper tube body and a lower tube body, and the guide plate is arranged on the upper tube body, and the annular cylinder, the annular liquid receiving groove, and the gas branch channel are arranged on the lower tube body, thereby realizing the production and installation of the full-diameter liquid-free device of the present invention.

[0032] In summary, the present invention can make full use of the production layer pressure without occupying the central channel of the production string, thereby improving the gas-liquid carrying capacity of the oil and gas wells and improving the oil and gas recovery rate. The present invention can be applied not only to oil wells but also to gas wells, solving the problem of liquid slippage in the production process of oil and gas wells, as well as the problems of gas well flooding and low natural gas recovery rate caused by the decrease in the liquid-carrying capacity of the gas wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the structure of an upper tube body in one embodiment of the present invention;

[0035] Figure 3 It is a schematic structural diagram of a lower tube body in one embodiment of the present invention;

[0036] Figure 4 It is a structural schematic diagram of another embodiment of the present invention;

[0037] Figure 5 for Figure 4 A magnified image of point A;

[0038] Figure 6 It is a structural schematic diagram of another embodiment of the present invention;

[0039] Figure 7 for Figure 6 Cross-sectional view along direction BB;

[0040] Figure 8 It is a schematic structural diagram of a liquid accumulation-free oil and gas pipe for an oil and gas well in one embodiment of the present invention;

[0041] Fig. 9 It is a schematic diagram of the structure when the present invention is used;

[0042] Fig.10 It is a comparison diagram of the first gas lift induced blowout and the second gas lift induced blowout in the effect example of the present invention;

[0043] Fig.11 This is a production diagram 12 days after the well handover of the present invention in the effect example of the present invention.

[0044] In the figure: 1. tube body, 2. main gas channel, 3. annular liquid receiving groove, 4. annular guide plate, 5. bending passage, 6. annular cylinder, 7. annular cavity, 8. air inlet, 9. first channel, 10. annular air outlet; 11. annular connecting plate, 13. inner ring plate, 14. outer ring plate, 15. oil and gas pipe, 16. anti-slip injection hole structure, 17. upper tube body, 18. lower tube body, 19. annular groove, 20. annular tube, 21. air supply channel, 22. jet hole rotating block, 23. jet hole, 24. short tapered hole, 25. fine hole, 26. long tapered hole, 27. limiting boss, 28. steel pad, 29. annular sealing pad, 30. annular groove. DETAILED DESCRIPTION

[0045] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0047] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] The present invention is described in further detail below with reference to the accompanying drawings.

[0049] In the present invention, the term "liquid accumulation free" is explained as follows: slippage refers to the phenomenon that in a gas-liquid two-phase pipe flow, gas exceeds the flow of liquid due to the density difference between gas and liquid; due to the existence of the slippage phenomenon, the gas phase in the wellbore of the oil and gas well is insufficient to carry the liquid phase, resulting in the liquid phase falling back to the bottom of the well, accumulating step by step to form liquid accumulation; liquid accumulation free means hindering the formation of liquid accumulation, preventing the production of oil and gas wells from being affected by the liquid accumulation in the production tubing, which is called liquid accumulation free.

[0050] Example 1

[0051] like Figure 1-3 and Figure 8 An embodiment of an oil and gas pipe for oil and gas wells free of liquid accumulation of the present invention is shown, comprising an oil and gas pipe 15 and a full-bore liquid-free device arranged at the top or bottom of the oil and gas pipe 15 and threadedly connected to the oil and gas pipe 15; the full-bore liquid-free device comprises a pipe body 1, a main gas channel 2 arranged at the center of the pipe body 1, an annular groove 30 arranged on the inner wall of the pipe body 1 and connected to the main gas channel, a gas branch channel arranged in the annular groove 30 and an annular liquid receiving groove 3 with an upward opening, and the gas branch channel passes through the liquid receiving groove. When the gas-liquid mixture rises in the pipe string, the gas-liquid mixture is rubbed by the inner wall of the production pipe string, and the speed will gradually decrease. The friction resistance of the production pipe string is transmitted from the periphery of the pipe to the center of the pipe due to the viscosity of the gas-liquid mixture. Therefore, the flow rate of the gas-liquid mixture decreases quickly at the position close to the inner wall of the production pipe string, while the flow rate of the gas-liquid mixture in the center of the production pipe string decreases slowly. This causes liquid to fall along the inner wall of the pipe body 1, thereby causing flooding of the gas well. In order to solve this problem, the present invention designs a full-diameter liquid-free device By arranging a liquid receiving groove and a guide plate on the inner wall of the pipe body 1, and arranging a gas branch channel passing through the liquid receiving groove on the inner wall of the pipe body 1, the liquid falling along the pipe wall is guided to the liquid receiving groove through the guide plate to prevent it from sliding to the bottom of the well. In the process of oil and gas rising along the central gas channel, part of the gas is diverted by the gas branch channel, so that the liquid in the liquid receiving groove is taken out in the process of passing through the liquid receiving groove, and continues to rise along the production pipe string, thereby avoiding the problem of more and more liquid accumulation in the liquid receiving groove, resulting in overflow of the accumulated liquid and continued sliding after the overflow.

[0052] As an embodiment of the present invention, an oil and gas pipe for oil and gas wells free of liquid accumulation is further provided with an annular guide plate 4 on the top wall of the annular groove 30, the inner wall of the annular guide plate 4 is smoothly connected to the inner wall of the upper part of the pipe body 1, and the lower part of the annular guide plate 4 is inserted into the annular liquid receiving groove 3, thereby forming a bent passage 5 in the annular liquid receiving groove 3. The present invention provides a bent passage in the liquid receiving groove, and the branch gas enters from one end of the bent passage and flows out from the other end, which maximizes the contact time between the gas and the liquid in the liquid receiving groove and increases the liquid carrying capacity of the gas.

[0053] As an embodiment of an oil and gas pipe for oil and gas wells without liquid accumulation of the present invention, an annular cylinder 6 is arranged on the inner wall of the pipe body 1, and the annular cylinder 6 and the inner wall of the pipe body 1 enclose an annular cavity 7, the main gas channel is arranged at the center of the annular cylinder 6, the annular liquid receiving groove 3 is arranged on the annular cylinder 6, and the annular cylinder 6 is also provided with a plurality of air inlets 8 connecting the main gas channel and the annular cavity 7.

[0054] As an embodiment of an oil and gas pipe for oil and gas wells free of liquid accumulation of the present invention, the annular cylinder 6 is connected with the top wall gap of the annular groove 30, so as to form a first channel 9 connecting the annular cavity 7 and the bending channel and an annular gas outlet 10 connecting the bending channel and the main gas channel;

[0055] The air inlet 8, the annular cavity 7, the first channel 9, the bent passage 5, and the annular air outlet 10 are connected in sequence to form the gas branch channel.

[0056] As an embodiment of the present invention, the annular tube 6 includes an annular connecting plate 11 arranged on the inner wall of the pipe body 1, and an annular liquid receiving groove 3 arranged on the annular connecting plate 11. When the natural gas is ejected from the gas branch pipeline, on the one hand, the upward airflow can form an upward force on the liquid on the pipe wall, further blocking the downward movement of the liquid on the pipe wall, and on the other hand, it also cuts off the channel for the liquid to slide down along the inner wall of the pipe body 1, and also avoids the downward movement of the liquid on the inner wall of the pipe body 1 to a certain extent.

[0057] As an embodiment of the oil and gas pipe for oil and gas wells free of liquid accumulation of the present invention, the air inlet 8 is arranged on the annular connecting plate 11 , and the position of the air inlet 8 is higher than the lowest point of the annular cavity 7 .

[0058] As an embodiment of the present invention, the annular liquid receiving groove 3 is enclosed by an inner ring plate 13 and an outer ring plate 14, and the upper surface of the inner ring plate 13 is lower than the upper surface of the outer ring plate 14. On the one hand, the present invention sets the upper surface of the inner ring plate 13 of the annular liquid receiving groove 3 lower than the outer ring plate 14, and on the other hand, sets the air inlet 8 connecting the main gas channel 2 and the annular cavity 7 to be higher than the bottom wall of the annular cavity 7, thereby preventing the liquid in the annular liquid receiving groove 3 from overflowing over the outer ring plate 14 into the annular cavity 7, reducing the accumulation of liquid in the annular cavity 7, and preventing the gas branch channel from being blocked by a small amount of liquid accumulated at the bottom of the annular cavity 7, thereby affecting the air intake of the gas branch channel.

[0059] As an embodiment of an oil and gas pipe for oil and gas wells free of liquid accumulation of the present invention, the pipe body 1 includes an upper pipe body 17 and a lower pipe body 18, the outer wall of the upper pipe body 17 is provided with an annular groove 19, the bottom of the lower pipe body 18 is provided with an annular tube 20 adapted to the annular groove 19, the annular tube 20 is arranged in the annular groove 19 and is threadedly connected to the annular groove 19. In addition, as another embodiment, the annular tube 20 and the annular groove 19 can also be connected by interference fit, bonding, welding and other connection methods. The full-bore liquid-free device of the present invention is assembled from an upper pipe body 17 and a lower pipe body 18, and a guide plate is arranged on the upper pipe body 17, and an annular cylinder 6, an annular liquid receiving groove 3, and a gas branch channel are arranged on the lower pipe body 18, thereby realizing the production and installation of the full-bore liquid-free device of the present invention.

[0060] Example 2

[0061] like Figure 1-8 The embodiment of the present invention of an oil and gas well free of liquid accumulation is shown, which is the same as the embodiment 1, except that the pipe body 1 is further provided with an anti-slip gas injection hole structure 16; the anti-slip gas injection hole structure 16 includes a hole opened on the pipe body 1 and used to connect the outside of the pipe body 1 with the main gas channel 2. Figure 6 and / or gas branch channels Figure 4 The air supply channel 21 is tilted, and the distance from the top of the air supply channel 21 to the central axis of the tube body 1 is smaller than the distance from the bottom to the central axis of the tube body 1. A jet hole swirl block 22 is provided in the air supply channel 21, and a jet hole 23 is provided on the jet hole swirl block 22. The setting of the air supply channel 21 of the present invention can send the gas outside the oil and gas pipe 15 into the oil and gas pipe 15, which plays a role in diluting the gas-liquid mixture inside the oil and gas pipe 15 and reducing the density of the gas-liquid mixture, thereby achieving the purpose of preventing the liquid inside the oil and gas pipe 15 from slipping off. The setting of the jet hole 23 can speed up the flow speed of the air supply gas, thereby increasing the flow speed of the gas-liquid mixture in the oil and gas pipe 15 and preventing the liquid in the oil and gas pipe 15 from slipping off.

[0062] As an embodiment of an oil and gas pipe for oil and gas wells without liquid accumulation of the present invention, the jet hole 23 includes a short tapered hole 24, a thin hole 25 and a long tapered hole 26 which are arranged and connected in sequence according to the gas flow direction, and the taper of the short tapered hole 24 is greater than the taper of the long tapered hole 26.

[0063] As an embodiment of an oil and gas pipe for oil and gas wells free of liquid accumulation of the present invention, a limiting boss 27 is provided in the gas supply channel 21 , and a steel gasket 28 and an annular sealing gasket 29 are provided between the limiting boss 27 and the jet hole rotary block 22 .

[0064] As an embodiment of an oil and gas pipe for oil and gas wells free of liquid accumulation of the present invention, the gas supply channel 21 is eccentrically arranged in the horizontal direction with the central axis of the pipe body 1 as the center of the circle; thereby, a spirally rotating upward airflow can be formed in the main gas channel 2 or the gas branch channel to avoid liquid slippage.

[0065] Method of use of the present invention:

[0066] When the present invention is used, Fig. 9 As shown, several oil and gas well liquid-free oil and gas pipes of Example 1 and several oil and gas well liquid-free oil and gas pipes of Example 2 are connected end to end in sequence to form a production string. When connecting, one oil and gas well liquid-free oil and gas pipe of Example 2 is set for every several oil and gas well liquid-free oil and gas pipes of Example 1; the lower the production string is, the fewer the number of oil and gas well liquid-free oil and gas pipes of Example 1 between adjacent oil and gas well liquid-free oil and gas pipes of Example 2.

[0067] The production string of the present invention is placed in the casing of an oil and gas well for use. During oil and gas production, under the action of the full-diameter liquid-free oil and gas pipe of the oil and gas well liquid-free oil and gas pipe of Example 1 and Example 2, the production string can prevent the liquid on the inner wall of the pipe body 1 from falling without additional power. At intervals, an oil and gas well liquid-free oil and gas pipe of Example 2 is set. Under the action of the anti-slip gas injection hole structure 16 on the liquid-free oil pipe of Example 2, a certain amount of gas can be introduced into the production string to reduce the density of the gas-liquid mixture in the production string. Under the action of the jet hole 23, the flow rate of the gas-liquid mixture in the production string can be increased. When the gas supply channel 21 of the anti-slip gas injection hole structure 16 is eccentrically set, a spiral upward moving airflow can be formed in the production string, and the Bernoulli principle of the supplied gas is used to form a lifting force on the original gas-liquid mixture in the production string to prevent it from slipping.

[0068] In summary, the present invention can make full use of the production layer pressure without occupying the central channel of the production string, thereby improving the gas-liquid carrying capacity of the oil and gas wells and improving the oil and gas recovery rate. The present invention can be applied not only to oil wells but also to gas wells, solving the problem of liquid slippage in the production process of oil and gas wells, as well as the problems of gas well flooding and low natural gas recovery rate caused by the decrease in the liquid-carrying capacity of the gas wells.

[0069] Effect example: Application example of SuXX-XXH natural gas self-flowing well

[0070] Since the contents of each operation section before and after the construction are different and the time used is quite different, it is impossible to compare and analyze the changes of the drainage one by one. Therefore, in the inducing stage of the natural gas self-flowing well, the present invention compares the changes of the gas lift drainage and the hourly drainage volume of the gas lift inducing the gas lift and the gas lift inducing the gas lift inducing the gas lift ( Fig.10 ), and after the well is handed over, the gas production data when the present invention is used for stable production is recorded ( Fig.11), the result is as follows:

[0071] 1. The first gas lift induced blowout (the traditional gas lift induced blowout before the production string of the present invention is run): the well was opened for 3 hours before gas lift, 4 hours after gas lift, and the well was opened for 46 hours after stopping the well lift, a total of 53 hours, the highest casing pressure was 20.8MPa, the lowest was 2.1MPa, and the cumulative liquid output was 61.5m 3 , the maximum liquid output per hour is 8.4m 3 The average liquid output per hour is about 1.16m 3 ;

[0072] 2. Second gas lift induced blowout (using the production string of the present invention): After the production string of the present invention replaced the production string in the conventional gas lift technology, i.e. the technology of the present invention, the gas lift lasted for 26 hours, the well was shut down after the lifting was stopped for 29 hours, a total of 55 hours, and the cumulative liquid output was 129.8m 3 , the maximum liquid output per hour is 8.1m 3 The average liquid output per hour is about 2.36m 3 .

[0073] From the above results we can see that:

[0074] 1. After the gas lift well is transformed according to the present invention, when the time used for gas lift exceeds that before the transformation, the average liquid output per hour of the gas lift is still more than twice the average liquid output per hour before the transformation.

[0075] 2. In the traditional gas lift technology, the maximum pressure of the gas lift operation is 20.8MPa, but after applying the present invention, the maximum gas lift pressure is only 13.58MPa. Therefore, it can be explained that compared with the traditional gas lift technology, the gas lift pressure required by the present invention is lower.

[0076] Lower pressure required for post-start wells;

[0077] 3. From Fig.10 It can be seen that during the first gas lift to induce blowout, the casing pressure suddenly dropped after the gas lift opened the pipe pin, and the casing pressure was 5.9 MPa when the pump was stopped, resulting in insufficient casing pressure during blowout. When the present invention is used, when the pressure reaches a maximum of 13.58 MPa, a slow drop occurs. After the gas lift is stopped, the casing pressure is 13.05 MPa and the pressure still keeps dropping slowly. Therefore, it can be proved that the present invention can make full use of the pressure stored in the casing during gas lift to ensure stable production.

[0078] 4. Fig.11This is the production situation 12 days after the well was handed over. It is divided into 4 stages from left to right: The first stage is the blue area, which is the first well opening after the well was handed over for 20 hours. Judging from the production temperature, the water content is relatively high. The second stage is the black area, and the production situation in this area is shut-in. The third stage is the red area. During this stage, the production fluctuation is relatively large, and large amounts of gas and liquid are discharged intermittently. It is judged that the well-killing fluid entering the bottom layer is being produced. (After the gas lift is completed after the construction, the remaining fracturing fluid and well-killing fluid in the well total 201m 3 ); The fourth stage is the green area. After a large amount of liquid is produced in the well, the production tends to be stable and stable gas-liquid mixed production begins.

[0079] The above-described embodiments are only preferred embodiments of the present invention, and are not exhaustive of the feasible implementations of the present invention. For those skilled in the art, any obvious changes made thereto without departing from the principles and spirit of the present invention should be considered to be included in the scope of protection of the claims of the present invention.

Claims

1. A full-bore liquid-free device, characterized in that: It comprises a tube body (1), a main gas channel (2) arranged at the center of the tube body (1), an annular groove (30) arranged on the inner wall of the tube body (1) and connected to the main gas channel, a gas branch channel arranged in the annular groove (30) and an annular liquid receiving groove (3) with an opening facing upwards, the gas branch channel passing through the annular liquid receiving groove (3); An annular guide plate (4) is also provided on the top wall of the annular groove (30); the inner wall of the annular guide plate (4) is smoothly connected to the inner wall of the upper part of the tube body (1); the lower part of the annular guide plate (4) is inserted into the annular liquid receiving groove (3), thereby forming a bent passage (5) in the annular liquid receiving groove (3); An annular cylinder (6) is arranged on the inner wall of the tube body (1), the annular cylinder (6) and the inner wall of the tube body (1) enclose an annular cavity (7), the main gas channel is arranged at the center of the annular cylinder (6), the annular liquid receiving groove (3) is arranged on the annular cylinder (6), and the annular cylinder (6) is also provided with a plurality of gas inlets (8) connecting the main gas channel and the annular cavity (7); The annular cylinder (6) is connected to the top wall gap of the annular groove (30), thereby forming a first channel (9) connecting the annular cavity (7) and the bending channel and an annular gas outlet (10) connecting the bending channel and the main gas channel; The annular liquid receiving groove (3) is enclosed by an inner ring plate (13) and an outer ring plate (14), and the upper surface of the inner ring plate (13) is lower than the upper surface of the outer ring plate (14).

2. A full-bore liquid-free device according to claim 1, characterized in that: The air inlet (8), the annular cavity (7), the first channel (9), the bent passage (5), and the annular air outlet (10) are connected in sequence to form the gas branch channel.

3. A full-bore liquid-free device according to claim 1, characterized in that: The annular cylinder (6) comprises an annular connecting plate (11) arranged on the inner wall of the tube body (1), and an annular liquid receiving groove (3) arranged on the annular connecting plate (11).

4. A full-bore liquid-free device according to claim 1, characterized in that: The air inlet (8) is arranged on the annular connecting plate (11), and the position of the air inlet (8) is higher than the lowest point of the annular cavity (7).

5. A full-bore liquid-free device according to claim 1, characterized in that: The tube body (1) comprises an upper tube body (17) and a lower tube body (18); the outer wall of the upper tube body (17) is provided with an annular groove (19); the bottom of the lower tube body (18) is provided with an annular tube (20) adapted to the annular groove (19); the annular tube (20) is arranged in the annular groove (19) and is bonded, welded or detachably connected to the annular groove (19).

6. A full-bore liquid-free device according to claim 1, characterized in that: The tube body (1) is also provided with an inclined gas supply channel (21) which is connected to the outside of the tube body (1) and the main gas channel (2) and / or the branch gas channel. A jet hole swirl block (22) is provided in the gas supply channel (21), and a jet hole (23) is provided on the jet hole swirl block (22); The distance from the top end of the air supply channel (21) to the central axis of the tube body (1) is smaller than the distance from the bottom end to the central axis of the tube body (1).

7. An oil and gas pipe for oil and gas wells free of liquid accumulation, characterized in that: It comprises an oil and gas pipe (15) and a full-bore liquid-free device arranged at the top or bottom of the oil and gas pipe (15) and according to any one of claims 1 to 6, wherein the oil and gas pipe (15) is integrally connected, welded or threadedly connected to the full-bore liquid-free device.

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